This application is to continue our Southern California Environmental Health Sciences Center whose main purposes are 1) to study the effects of environmental exposures on humans; 2) to determine host factors (genetic and other) influencing response to these exposures; and 3) to inform the public. To accomplish these goals we bring together an interdisciplinary team of investigators from two major Southern California universities: USC and UCLA. The research of our Center features several interdisciplinary cornerstones: detailed exposure assessment, including toxicokinetics and biomarkers; cutting edge study design, including the most powerful statistical and epidemiologic approaches; and the basic sciences, including physiology, molecular biology, genetics, chemistry and engineering. The foci of the Center cover a wide range of problems and address environmental exposures of public health importance including indoor and outdoor air pollution, pesticides, aflatoxins, radiation and passive smoking. The four Research Cores consist of: the Respiratory Effects Research Core (Director: Peters); the Exposure Assessment Research Core (Director: Froines); the Cancer Research Core (Director: Ross); and the Study Design and Statistical Methodology Research Core (Director: Thomas). The three Facility Cores consist of: the Molecular Biology, Sample Processing and Storage Facility Core (Director: Dubeau); the Exposure Assessment and GIS Facility Core (Director: Hinds); and the Biostatistics Facility Core (Director: Gauderman). The Center also features an integrative Core for Community Outreach and Education (COEP; Director: Hricko). The Center is structured to promote interdisciplinary research and linkage between the research and the COEP. Processes creating these interactions include research initiatives, seminar series, pilot projects, research focus groups, workshops and retreats. The previous nine years of support for this Center have resulted in recruitment of new investigators, more investigators working on environmental health problems, increasing funding support, more interaction between researchers from different disciplines and a greater production of research findings relevant to answering critical public health questions. The Center also has developed research initiatives for the next five years that focus the interdisciplinary team of investigators on important environmental health problems and is poised to build on its success in facilitating cutting edge environmental health sciences research.